Device and method for determining parameters

ABSTRACT

A system for determining quantities which influence the operating dynamics of a motor vehicle, the system containing at least two different control and/or regulating systems by which, independently of one another and independently of the driver, intervention measures which influence the vehicle dynamics may be performed with the help of suitable actuators, in response to one of these at least two different control and/or regulating systems carrying out an intervention influencing the operating dynamics of the vehicle, in each case the same quantity which describes the vehicle dynamics being altered by this intervention, at least two of the intervention measures influencing the vehicle dynamics being implemented in such a way that the same quantity which describes the vehicle dynamics is altered as little as possible by the intervention measures, and in the ideal case is not altered at all.

FIELD OF THE INVENTION

The invention relates to a system for determining quantities whichinfluence the operating dynamics of a motor vehicle.

DESCRIPTION OF RELATED ART

German Patent 44 19 131 describes an invention for a motor vehicle,preferably a passenger vehicle having a hydraulic anti-lock brake system(ABS). To resolve the general conflict in goals between braking distanceand driving stability with traditional ABS systems, the brakingpressures supplied to the brakes of the individual vehicle wheels areregulated completely independently of one another and exclusively as afunction of the individual locking risk of the individual vehicle wheelsdetermined in each case, so that the adhesion between the road surfaceand the wheel prevailing at the individual wheels is utilized to thebest possible extent and thus the shortest possible braking distance,i.e., stopping distance is achieved. In this way any trends towarddirectional instability, i.e., driving instability, that might occur arecompensated easily by a regulated steering system in which an additionalsteering angle which depends on the particular yaw rate of the vehicle,for example, is automatically superimposed on a basic steering angle,which may be determined manually by the driver by manipulation of thesteering wheel, for the purpose of maintaining driving stability of thevehicle.

German Patent 197 49 005 describes a device and a method for regulatingmovement variables representing the movement of the vehicle. This devicecontains first means for detecting variables representing the movementof the vehicle. The device also contains at least two regulating deviceswhich perform regulating interventions independently of one another tostabilize the vehicle with the help of suitable actuators based onvariables detected with the help of the first means. At least oneregulating device here intervenes in the steering of the vehicle.Furthermore, at least one regulating device intervenes in the brakesand/or in the engine of the vehicle and/or another regulating deviceintervenes in the chassis actuators. In addition, the device containssecond means using which signals and/or variables are determined on thebasis of the variables detected using the first means and then are usedto influence at least one of the at least two regulating devices atleast temporarily to stabilize the vehicle. At least one of the at leasttwo regulating devices then performs regulating interventions tostabilize the vehicle, uninfluenced by the second means, until beinginfluenced by the signals and/or variables determined with the help ofthe second means.

SUMMARY OF THE INVENTION

Although the publications described as belonging to the related art areconcerned with the task of regulating operating-dynamics variables, thepresent invention is related to the determination of quantities whichinfluence the operating dynamics of a motor vehicle.

The present invention relates to a system for determining quantitieswhich influence the operating dynamics of a motor vehicle,

-   -   the system containing at least two different control and/or        regulating systems by which, independently of one another and        independently of the driver, interventions influencing the        vehicle operating dynamics are able to be carried out with the        aid of suitable actuators,    -   in response to one of these at least two different control        and/or regulating systems carrying out an intervention        influencing the operating dynamics of the vehicle, in each case        the same quantity which describes the vehicle dynamics being        altered by this intervention,    -   at least two of the intervention measures which influence the        vehicle dynamics being implemented by two of these different        control and/or regulating systems so that the same quantity        which describes the vehicle dynamics is altered as little as        possible by these measures and in the ideal case is not altered        at all.

Due to the fact that the quantity describing the vehicle dynamicschanges as little as possible, a high measure of driving comfort isretained. At the same time due, to the measures described here, thevehicle does not get into a dangerous driving situation.

An advantageous embodiment of the system is characterized in that atleast two of the following control and/or regulating systems areprovided as the different control and/or regulating systems, namely

-   -   a control and/or regulating system which intervenes in the        brakes,    -   a control and/or regulating system which intervenes in the        engine,    -   a control and/or regulating system which intervenes in the        steering of the vehicle,    -   a control and/or regulating system which intervenes in the        vehicle shock absorbers and    -   a control and/or regulating system which intervenes in the        stabilizers.

It is also advantageous if the at least two interventions whichinfluence the vehicle dynamics are performed simultaneously. The term“simultaneously” is intended to mean here “essentially simultaneously”because a precise simultaneity in the mathematical sense is impossibledue to different switching times of actuators.

An advantageous embodiment is characterized in that the variable whichdescribes the vehicle dynamics and is altered as little as possible bythe interventions and in the ideal case is not altered at all is avariable which, when changed, has an influence on the transversedynamics of the vehicle.

Another advantageous embodiment is characterized in that the variablewhich describes the vehicle dynamics and which is altered as little aspossible by the interventions and in the ideal case is not altered atall is the yaw rate. A yaw rate sensor is already present in manyvehicles today. Therefore, in checking whether the yaw rate has changed,it is possible to use the output signals of this sensor without anysignificant additional effort.

It is also advantageous if the at least two different control and/orregulating systems include a control and/or regulating system whichintervenes in the steering of the vehicle and a control and/orregulating system which intervenes in the brakes of the vehicle. Forexample, this refers to an electrohydraulic brake (EHB) for the brakeinterventions and a steering controller for the steering intervention.Both of these systems allow very precise intervention, which isadvantageous for the present invention.

It is advantageous if the interventions of the at least two differentcontrol and/or regulating systems are performed only when the vehicle istraveling straight ahead. This driving state is the simplest to describein terms of vehicle dynamics and the vehicle may be regulated to a yawrate of zero for example.

An advantageous embodiment is characterized in that at least twointerventions which influence the vehicle dynamics are performed withgraduated intensity by the at least two different control and/orregulating systems. This makes it possible to determine characteristiccurves.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described in greater detail with referenceto the following drawings wherein:

FIG. 1 shows at the left a vehicle without simultaneous steering andbraking interventions and at the right a vehicle with simultaneoussteering and braking interventions.

FIG. 2 shows the interaction of the vehicle dynamics regulator with thevehicle and the identification block.

FIG. 3 shows the sequence of the method performed in the identificationblock.

FIG. 4 shows a vehicle with forces acting on it.

DETAILED DESCRIPTION OF THE INVENTION

The core of this exemplary embodiment is the active use of the steeringand the brakes to determine characteristic quantities. The term“characteristic quantities” is understood here to refer to the followingquantities, for example:

-   -   wheel loads    -   brake characteristic curves (hysteresis, slope)    -   tire characteristic curves (lateral rigidities, longitudinal        rigidities)    -   steering characteristic quantities    -   adhesion coefficients

The core of the present invention is linking the steering and brakinginterventions in such a way that they do not have any significant orperceptible influence on the transverse dynamic driving performance.This method is explained in greater detail in conjunction with FIG. 1.The left of FIG. 1 shows a vehicle without braking and steeringintervention, and the right shows a vehicle with targeted braking andsteering intervention. The solid black blocks represent the wheels ofthe vehicle. In both cases the vehicle should follow a certain drivingdirection at the velocity v which corresponds to the driver's intent.This driving direction is depicted in FIG. 1 by the vertical arrowpointing upward.

The following three imaginary experiments will now be performed for thevehicle on the right in FIG. 1:

1. There is only one steering intervention which causes the two frontwheels to turn to the left (the steering angle is δ as shown in FIG. 1).There is no braking intervention. Now a yaw torque MpsiL occurs,rotating the vehicle to the left. As a result the vehicle travels alonga curve to the left.

2. There is only a braking intervention on the right rear wheel (withbraking force Fb as shown here) but there is no steering intervention.As a result the vehicle executes a yawing motion about the right rearwheel causing the vehicle to turn to the right. The yaw torque here isMpsiR.

3. Now the above-mentioned steering intervention as well as theabove-mentioned brake intervention are performed at the same time. Thustwo competing effects occur which tend to steer the vehicle both to theleft and to the right. It is possible to select the intensity of thesteering intervention (measurable by steering angle δ, for example) andthe intensity of the brake intervention (measurable by the pressure inthe wheel brake cylinder of the right rear wheel in the case ofhydraulic or electrohydraulic brakes (EHB), for example, or measurablevia the current in the case of electromechanical brakes (EMB)), so thatthe two competing effects cancel each other out and the vehiclecontinues to travel straight ahead. This means that yaw torques MpsiLand MpsiR are equal in absolute value but have different signs.Therefore, the yaw torques cancel each other out and the vehiclecontinues to travel straight ahead. This is expressed mathematically byMpsi=MpsiR+MpsiL=0. Yaw torque Mpsi is a torque having the dimension Nm.

Accurately and precisely regulated brake interventions are possible forexample using an electrohydraulic brake (EHB), and accurately andprecisely regulated steering interventions are possible with an FLSsteering controller (FLS=vehicle dynamics steering system). Since thereis no perceptible influence on the transverse dynamic drivingperformance through the combination of the two interventions, drivingcomfort does not suffer as a result of such a method. This also preventsany safety risk due to lateral movement of the vehicle.

FIG. 2 illustrates the device for identification of the characteristicquantities where it is embedded in the system which includes the vehicledynamics regulator and the motor vehicle.

The following symbols and blocks are used:

-   Fw=quantities describing the driver's intent,-   St=manipulated variables,-   Sen=sensor signals and-   Kg=characteristic quantities.-   199=driver-   200=vehicle dynamics regulator-   201=vehicle (including sensors and actuators)-   202=characteristic quantity identification block

The topological structure of FIG. 2 is as follows:

-   -   Block 199 supplies quantities Fw to block 200.    -   Block 200 supplies quantities St to blocks 201 and 202.    -   Block 201 supplies quantities Sen to block 202.    -   Block 202 supplies the quantity Kg to block 200.

The blocks contained in FIG. 2 are described in greater detail below:

-   -   Block 199 represents the driver of the vehicle, who makes        available quantities Fw describing the driver's intent. These        include quantities such as the steering wheel position, the        brake pedal position, the gas pedal position and the changes in        these quantities over time.    -   Block 200 is the vehicle dynamics regulator which may be a        vehicle dynamics regulating system (FDR=vehicle dynamics        regulation, ESP=electronic stability program), for example, a        traction control (TC) or an anti-lock brake system (ABS).        Important input quantities for the present invention include        driver's intent Fw and characteristic quantities Kg.    -   Block 201 represents the vehicle which responds to the        manipulated variables coming from block 200. This response is        manifested, for example, in actuation of actuators in the        vehicle (brakes, engine control, steering intervention) and then        in the geometric shape of the curve traveled by the vehicle.        Block 201 receives the manipulated variables as input signals.        The output signals from block 201 are sensor signals Sen which        are supplied by sensors that may be mounted on the vehicle. It        is quite conceivable here to include sensors that supply        information regarding the vehicle (e.g., location, speed) and        are not mounted on the vehicle. Block 201 also includes the        sensors belonging to the vehicle (brake pressure, steering        angle, yaw rate, etc.) and actuators (brakes, steering, etc.).    -   Block 202 is the identification block. The characteristic        quantities are calculated in this block and then sent to the        vehicle dynamics regulator. The identification block receives        manipulated variables and sensor signals as input signals.

In block 201, for example, sensors are available for detection of thefollowing variables:

-   -   brake pressure of the individual wheel brake cylinders, i.e.,        the pressure in the brake circuit and/or the brake current in        the case of the electromechanical brake (EMB)    -   steering angle    -   yaw rate    -   transverse acceleration    -   wheel rotational speeds or wheel speeds

The variables measured by the sensors are indicated in FIG. 2 as sensorsignals Sen. In addition to the sensor signals, manipulated variables Stand characteristic quantities Kg also occur in FIG. 2.

Manipulated variables are understood to be the variables which areregulated to a stable state by vehicle dynamics regulator 200. Examplesof this include the electric current through an electric steering deviceand/or an electric steering controller or the brake pressure in theindividual wheel brake cylinders. These quantities are not detecteddirectly by sensors but instead are calculated in vehicle dynamicsregulator 200. The controllers and actuators in the vehicle areinfluenced by these manipulated variables.

The characteristic quantities are identified in block 202. It ispossible to differentiate between vehicle characteristic quantities andenvironmental characteristic quantities. The vehicle characteristicquantities may include, for example, wheel loads, brake characteristiccurves (hysteresis, steepness), tire characteristic curves,inflatable-spare-tire recognition or steering characteristic quantities.The environmental characteristic quantities may include, for example,adhesion coefficients between the tire and road.

The instantaneous identification of the characteristic quantities inblock 202 is based on the comparison between the available signals(manipulated variables, sensor signals) and the values estimated usingan internal model in block 202. Through this comparison thecharacteristics quantities that are being sought are identified so thatthey are available for the next computation step in vehicle dynamicsregulator 200 and in the model in block 202. To be able to perform theidentification, the manipulated variables and/or the sensor signals mustoften be different from zero. This is a very significant restrictionwhich may have a great influence on the efficiency of vehicle dynamicsregulators. For example, in certain driving states such as a freelyrolling vehicle, the vehicle dynamics regulators are unable to estimatecertain characteristic quantities.

FIG. 3 illustrates the method for identification of characteristics.

The individual blocks here have the following meanings:

-   Block 300: Inquiry whether an identification of characteristic    quantities is feasible at all using the manipulated variables    currently available.-   Block 301: Inquiry whether an identification is necessary at all.-   Block 302: Performing mutually compensating steering and braking    interventions.-   Block 303: Identification of the characteristic quantities.-   Block 304: Implementing safety measures.-   Block 305: Adaptation of the regulator.-   Block 306: Time incrementation t=t+1

The topology of FIG. 3 is as follows:

-   -   In block 300 there is an inquiry as to whether an identification        is feasible. If the answer is “yes” (shown as “yes” in FIG. 3)        then the sequence proceeds to block 303. If the answer is “no”        (shown as “no” in FIG. 3) then the sequence branches off to        block 301.    -   In block 301 there is another inquiry as to whether an        identification is necessary. If the answer is “yes” (shown as        “yes” in FIG. 3), then the sequence continues to block 302. If        the answer is “no” (shown as “no” in FIG. 3), then the sequence        branches off to block 306.    -   The output signals of block 303 are sent to blocks 304 and 305.    -   The output signals of block 302 are sent to block 303.    -   The output signals of blocks 304 and 305 are sent to block 306.    -   The output signals of block 306 are sent to block 300.

The layout of FIG. 3 will now be explained in detail. In block 300 it isascertained whether the identification of the characteristic quantitiesis feasible with the manipulated variables currently available (e.g.,the instantaneous steering angle or the instantaneous brake pressure).If the identification is feasible, then it is performed in block 303. Ifthe identification is not feasible at the moment, then it is determinedin block 301 whether an identification is necessary at all at thepresent point in time. If an identification is not necessary at thepresent point in time, then the sequence starts again in block 300 at alater point in time. This is indicated by the incrementation of time(t=t+1) which is performed in block 306. However, if an identificationis necessary at the current point in time, then the compensatingsteering and braking interventions are set in block 302. Theseinterventions (and thus the manipulated variables on which they arebased) are linked so that the driver senses little or no influence.Identification of the characteristic quantities is then performed inblock 303. After successful identification, either safety measures areinitiated in block 304 (an example of this is identification of a tirepressure loss in which case a restriction of the maximum vehicle speed,for example, might be considered as a safety measure) and/or there is anadaptation of vehicle dynamics regulator 200 in block 305. Adaptation ofthe vehicle dynamics regulator is to be understood for example asadapting the model or characteristic curves implemented in it to thecharacteristic quantities currently determined. After implementing thesafety measures (block 304) or implementing the adaptation of theregulator (block 305), the time is incremented in block 306 and thenanother check as to whether an identification of the characteristicquantities is feasible using the current manipulated variables begins inblock 300.

The exemplary embodiment is to be made more specific below. Yaw momentMpsi may be expressed in general as a function f1 of longitudinal forcesFL acting on the vehicle and lateral force FS acting on the vehicle:Mpsi=f1(FL, FS).

Yaw moment Mpsi is closely related to yaw rate psi occurring then(essentially the Newtonian motion equation), so yaw rate psi occurringmay thus also be expressed as a function of FL and FS.

In the example according to FIG. 1, the front wheels are slightlysteered, i.e., lateral forces occur on the front wheels. These depend oncoefficient of friction μ between the tire and the road surface,steering angle δ and the normal forces acting on these wheels (=tirecontact forces) Fnvl and Fnvr (Fnvr=normal force right front,Fnvl=normal force left front):FS=f2(μ, δ, Fnvr, Fnvl).

The right rear wheel is braked. The braking force depends on brakingpressure pB on this wheel, coefficient of friction μ and tire contactforce Fnhr (=normal force right rear):FL=f3(μ, pB, Fnhr).

Now the following considerations shall be formulated:

-   -   It is now possible to express yaw rate psi as a function of μ,        δ, Fnvr, Fnvl, pB and Fnhr:        psi=f4(μ, δ, Fnvr, Fnvl, pB, Fnhr)  (1)    -   This is an extra equation. This means that with a knowledge of        psi, coefficient of friction μ may be determined from this        equation, for example. Wheel brake pressure pB, steering angle δ        or even the normal forces may also be determined from this        equation.    -   However, if yaw rate psi is different from zero, this is        associated with impaired driving comfort or even a safety risk        for the vehicle and the driver (lateral movement of the vehicle        not intended by the driver).    -   The invention described here makes it possible to achieve yaw        rate psi=0, while at the same time a wheel brake pressure which        is different from zero and a steering angle different from zero        prevail. This permits identification of quantities through an        extra equation without any negative effect on driving comfort or        driving safety.

The goal of achieving a yaw rate of psi=0 is appropriate in the case ofdriving straight ahead in particular. This means that the vehiclecontinues to travel straight ahead even while the steering and brakingintervention measures are being performed. In the case of turning acorner, the steering and braking interventions may be regulated in sucha way that yaw rate psi remains constant.

This state of affairs is depicted graphically again in FIG. 4, where thecenter of gravity in the middle of the vehicle is labeled as 401. Bysteering the front wheels, a force FS acts to the left. This force tendsto rotate the vehicle to the left about the center of gravity. Brakingforce Fb and/or longitudinal force FL acts toward the rear on the rightrear wheel. This force tends to move the vehicle to the right around thecenter of gravity. If the moments exerted by these forces are inequilibrium, there is no rotational movement of the vehicle about thecenter of gravity and thus there is no yawing motion. Yaw rate psi iszero. Although there is a minor (braking) influence on the longitudinalmovement of the vehicle, it does not constitute a safety risk.Furthermore, this braking influence may be compensated by increasing theengine torque.

Another point will also be explained here. Different values may beselected for the steering angle. For example, it is possible to beginwith a steering angle of 1 degree and then shortly thereafter increasethe steering angle to 2 degrees, etc. This means that a sequence ofdifferent steering angles is used. In parallel with this, a sequence ofdifferent braking pressures, i.e., braking forces, is applied to theright rear wheel because the yaw torque must always be compensated (andthus the yaw rate must always be negligible).

Thus new numerical values for the steering angle and the brake pressureare used at each point in this sequence in the equation psi=0, yieldinga sequence of equations.

The axle load distribution in the longitudinal direction of the vehicleis also explained in further detail. In a simple approximation, tirecontact force Fnij for wheel ij is obtained through the equationFnij=m*(static axle load distribution with respect to wheel ij)*(dynamicaxle load distribution with respect to wheel ij).In general it is true thatFnij=f5(m, static axle load distribution, dynamic axle loaddistribution).

The wheelbase in the longitudinal direction and the distances of theaxles from the center of gravity of the vehicle also enter into thestatic axle load distribution; for example, the load change in brakingoperations enters into the dynamic axle load distribution; m is the massof the vehicle.

If tire contact forces that have been actually determined are used informula 1 above for variables Fnvl, Fnvr and Fnhr, then a calculation ofmass m is possible from the equation psi=0.

The determination of a brake characteristic is also explained in furtherdetail. Let us assume that braking torque M is linked to brake pressurepB via function f6: M=f6(pB). As a simple linear approximation, M=c*pBmay even be assumed. The extra equation psi=0 (equation 1) may now beused to determine constant c or even function f6. To do so, for example,function f6 may be approximated by a polynomial having N unknowncoefficients. If a sequence having N different steering angles (and ofcourse the respective braking forces) is now run through, then byanalyzing the N equations thus obtained, the N unknown coefficients maybe determined. It is also conceivable to take hysteresis into account.

Determination of tire characteristics is also facilitated by the extraequation. To do so, the longitudinal and lateral forces acting on thetires are replaced by equations with parameters yet to be determined. Atleast one of these parameters may be determined by the extra equation.Several parameters may also be determined by this method. To do so, forexample, different steering angles δ are set, then compensated bydifferent braking forces so as to result in N different driving states,each with psi=0. This yields N different equations (each psi=0) whichmay be used for identification of N parameters (in mathematics, thiscorresponds to an equation system of N equations with N unknowns). Inthis method, the steering angle and braking intervention measures arethus implemented with graduated intensity.

Adhesion coefficients may also be determined by this method.

To do so, the longitudinal force and the lateral force on a tire areeach depicted as a function of the adhesion coefficient. The unknowncoefficients in these equations are identified as in the determinationof the tire characteristics by this method.

Identification of the characteristic quantities yields two essentialadvantages:

-   1. The accuracy of the regulator interventions is increased due to    the better adaptation of the vehicle dynamics regulator.-   2. Regular safety checks may be performed to ensure, for example,    that the actuators are functioning correctly.

To reduce the influence of the braking interventions on the longitudinaldynamics of the vehicle, the simultaneous implementation of activeengine intervention measures is also conceivable. For example this meansthat there is an increase in engine torque at the same time.

Instead of the simultaneous implementation of braking and steeringinterventions as described here (and possibly also engineinterventions), it is also possible to limit the determination ofbraking quantities to the brake and engine interventions. For example itis possible to brake the wheels that are not being driven while theengine torque is increased on the driven wheels. This also permitscompensation of the influences of these two measures on the longitudinaldynamics of the vehicle.

The entire principle which has been depicted for the steering and thebrakes may also be used for other active controllers, e.g., stabilizersor shock absorbers.

The method described here is recommended, for example, for the drivingstate when the vehicle is traveling straight ahead.

1-9. (canceled)
 10. A system for determining quantities which influencethe operating dynamics of a motor vehicle in the absence of hazardousdriving states, comprising at least two different regulating/controlsystems by which, independently of one another and independently of thedriver, interventions influencing the vehicle operating dynamics areable to be carried out with the aid of suitable actuators, wherein: inresponse to one of these different regulating/control systems carryingout an intervention (302) influencing the operating dynamics of thevehicle, in each case the same quantity (psi) which describes thevehicle dynamics being altered by this intervention, at least two of theintervention measures which influence the vehicle dynamics beingimplemented by two of these different regulating/control systems in sucha way that the same quantity (psi) which describes the vehicle dynamicsis not altered or is altered as little as possible by the interventionmeasures, and the quantities which influence the vehicle dynamicsincluding at least one of the wheel loads, brake characteristic curves,tire characteristic curves, steering characteristic quantities, adhesioncoefficients and inflatable-space-tire recognition.
 11. The systemaccording to claim 10, wherein at least two of the followingregulating/control systems are provided as different regulating/controlsystems: a regulating/control system which intervenes in the brakes, aregulating/control system which intervenes in the engine, aregulating/control system which intervenes in the steering of thevehicle, a regulating/control system which intervenes in the vehicleshock absorbers, and a regulating/control system which intervenes in thestabilizers.
 12. The system according to claim 10, wherein the at leasttwo intervention measures which influence the vehicle dynamics areperformed simultaneously.
 13. The system according to claim 10, whereinthe quantity which describes the vehicle dynamics is a quantity whosechange has an influence on the transverse dynamics of the vehicle. 14.The system according to claim 13, wherein the quantity which describesthe vehicle dynamics is the yaw rate (psi).
 15. The system according toclaim 11, wherein the at least two different regulating/control systemsinclude a regulating/control system which intervenes in the steering ofthe vehicle and a regulating/control system that intervenes in thebrakes of the vehicle.
 16. The system according to claim 10, wherein theinterventions of the at least two different regulating/control systemsare performed only when the vehicle is traveling straight ahead.
 17. Thesystem according to claim 10, wherein at least two intervention measureswhich influence the vehicle dynamics are performed by the at least twodifferent regulating/control systems with graduated intensity.
 18. Amethod for determining quantities which influence the operating dynamicsof a motor vehicle, based on a system containing at least two differentregulating/control systems by which, independently of one another andindependently of the driver, intervention measures (302) influencing thevehicle dynamics can be implemented with the help of suitable actuators,comprising: in response to one of these at least two differentregulating/control systems carrying out an intervention influencing theoperating dynamics of the vehicle, in each case the same quantity whichdescribes the vehicle dynamics being altered by this intervention,performing at least two of the intervention measures (302) which have aninfluence on the vehicle dynamics in such a way that the same quantity(psi) which describes the vehicle dynamics is not influenced or isinfluenced as little as possible by the intervention measures, andwherein the quantities that influence the vehicle dynamics include atleast one of wheel loads, brake characteristic curves, tirecharacteristic curves, steering characteristic quantities, adhesioncoefficients and inflatable-spare-tire recognition.
 19. The methodaccording to claim 18, wherein: before determining the quantitiesinfluencing the operating dynamics of a motor vehicle, it is ascertainedwhether a determination of these quantities is possible with themanipulated variables available at the moment in the vehicle, and in thecase when a determination of these quantities is possible, theinterventions (302) which influence the vehicle dynamics areimplemented.